Ex-employees, investors, gamers... it seems it would be far easier to compile a list of people who are not dissatisfied with the current CDPR.
I'd place my bet on a former employee or a disgruntled gamer. I'm old enough to remember well the Half Life 2 leak. Turned out it was true and it was the works of a single German kid, a fan of the series even, who was angry at the company for the repeated delays.
Investors are not interested in a stock plunder.
I think a Furious Fan would like to make damage (in leak info) not negotiate anything
Ex-employees - good point! Maybe have there been layoffs in CDPR? And a ex-employee would have access or info about CDPR systems